AggregateMessageSource.java

/*
 * Copyright (c) 2009-present the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.planet57.gshell.util.i18n;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import com.planet57.gossip.Log;
import org.slf4j.Logger;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * A message source which aggregates messages sources in order.
 *
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @since 2.0
 */
public class AggregateMessageSource
    implements MessageSource
{
  private static final Logger log = Log.getLogger(AggregateMessageSource.class);

  private final List<MessageSource> sources = new LinkedList<>();

  public AggregateMessageSource(final List<MessageSource> sources) {
    checkNotNull(sources);
    this.sources.addAll(sources);
  }

  public AggregateMessageSource(final MessageSource... sources) {
    this(Arrays.asList(sources));
  }

  public List<MessageSource> getSources() {
    return sources;
  }

  public String getMessage(final String code) {
    String result = null;

    for (MessageSource source : sources) {
      try {
        result = source.getMessage(code);
        if (result != null) {
          break;
        }
      }
      catch (ResourceNotFoundException e) {
        log.trace(e.toString(), e);
      }
    }

    if (result == null) {
      throw new ResourceNotFoundException(code);
    }

    return result;
  }

  public String format(final String code, final Object... args) {
    String result = null;

    for (MessageSource source : sources) {
      try {
        result = source.format(code, args);
        if (result != null) {
          break;
        }
      }
      catch (ResourceNotFoundException e) {
        log.trace(e.toString(), e);
      }
    }

    if (result == null) {
      throw new ResourceNotFoundException(code);
    }

    return result;
  }
}